Treatment of materials



ness of colourations thereon.

TREATMENT OF MATERIALS Charles Hugh Giles and Donald Graham Wilkinson, Blackley, Manchester, England, assignors to Imperial Chemical Industries Limited, a corporation of Great Britain .No Drawing. Application March 2, 1942, Serial No. 433,105. In Great Britain March 14, 1941 4 Claims. (Cl. 8-61) The present invention relates to the treatment by treating with N-methylaniline the product of of materials, which consist of or contain cellureacting acetanilide in benzene with phosphorus lose esters or ethers, in order to increase the fastpentachloride. N-phenyl-N'-p-tolyl-N-methylacetamidine is obtainable by condensing acet-p- Cellulose acetate artificial silk which has been luidine with N -methylaniline in phosphorus tricoloured by dyeing or printing, is known to be chloride.

liable to become affected when exposed to an These amidines may be applied to the dyed impure atmosphere such as that produced when material consisting of or containing cellulose coal gas is burned in an imperfectly ventilated esters or ethers in any convenient medium. The space, in such a way that the coloured parts of 10 amidines may be used in the form of solutions the material fade. This trouble is encountered, or dispersions. The application of the amidine for example, when the material is stored in a is conveniently effected by dipping the material warehouse where coal gas is burned. It will be it is desired to treat, into an aqueous dispersion understood that partic a y those parts of the of the desired amidine, squeezing out most of material suffer injury, which come into direct the adhering liquid and drying. The amidines contact with the atmosphere carrying the fumes may likewise be applied in solution in alcohol.

resulting from the combustion of the coal gas. The amidines must, however, be used in the form Thus in the case of piece goods the edges will of the free bases. The use of salts of amidines fade or indicate change of shade. In this mani not included in the invention. The material ner the material as a whole is disfigured and its may also be treated with the amidine in the manvalue diminished; indeed the material may be ner just described during the dyeing thereof, but

be spoiled as to become unsaleable. the amidine is preferably applied after the proc-. Whilst cellulose esters and ethers which have ess of dyeing, that is, to the already dyed matebeen dyed, are generally subject to the aforerial.

Said fading, the latter is p t u y liable to Under ordinary storage conditions the fad- Oc u wh t dycStulTS Which e een ing occasioned by coal gas fumes develops slowployed are derivatives of anthraquinone, especially nd more or less prolonged storage, dependly when the shades in question are blue or violet. ing on th state of the atmosphere and the We have now found that the above-described a nt of obnoxious gas present, is necessary fading can be considerably retarded, or indeed 3 before noticeable fading occurs, but fading for prevented, y the appl at t the material of testing purposes may be accelerated for instance organic compounds which are amidines as here-- by exposure t th fumes f burning coal gas in inbelow defined. a restricted space.

According to the invention material consisting For this purpose the dye patterns which t s of or containing esters or ethers of cellulose is required to submit to the action of thefumes, treated Wi a derivative of formamidine, in may be suspended within the upper end of an which each mtr gen atom bears a pheny1 iron pipe, conveniently 5-8 feet high and six whlch Itself may carry slmple groups inches in diameter, which is disposed vertically or atoms such as alkyl, alkoxy or haloge n above a lighted gas burner in such a manner in which the two remaining hydrogen atoms of 40 that the hot air arising from the burner and the formwmidine molecule Ijeplaced each laden with the fumes of the burnt gas is guided g i z g gig g g ig contammg not more upwards and caused to impinge upon the pat- Accordingly there may be employed in accordj Any form 9 apparatus embodying like ance with the present invention, for example, prmclple and dfasflgned that the matenal to NN, diphenylformamidme be tested can be immersed in an atmosphere comprising the products of combustion of the burn- (C6H5-NHCH=N C6H5) ing gas, may likewise be employed. In such an NN, diphenylacetamidine apparatus it is found that dyed material which is liable to fade 1n contact with the fumes of (C6H5 NH C(CH3)=N G6H5) burning gas, is noticeably impaired in shade in N-methyl-NN'-dipheny a ta the course of several hours, for instance, 6-10 (C6I'15-7N(CH3) -C (CH3) :N-C6H5) hours I 4 If patterns of dye cellulose acetate artificial N'ethyl'NN 'dlphenylacetamldme silk fabric which have been treated with amidines (CsHe-N( CzI-Is)-C(CHs)=NCsH5) according to the present invention, are esposed h lacetamidine in such an apparatus as described above, side by and N phenyl N p tolyl N met y side with the patterns of similarly dyed, untreated (C H -N(CH )-C(C}h)==N--C6H5) material, it is apparent that the treated ma- N-methyl-N:N'-diphenylaacetamldine is made 6 terial is possessed of considerably enhanced resistance to the fading action of the gas fumes. compared with the untreated material.

As has already been indicated above, the material which may be treated according to the invention is not confined to fabrics consisting wholly of cellulose esters or ethers, for example, cellulose acetate artificial silk fabric, but includes also, for instance, mixed fabrics of viscose and cellulose acetate artificial silks.

The following examples, in which the parts are by weight, illustrate but do not limit the invention.

Example 1 10 parts of NN-diphenylacetamidine are pebble-milled with 90 parts of water and /2 part of a 50% aqueous solution of the sodium salt of the condensation product from e-naphthalenesulphonic acid and formaldehyde. At the end of 24 hours, a fine dispersion has been produced. The dispersion is then diluted with water to a strength of 1%.

A piece of cellulose acetate artificial silk fabric which has been dyed with 1% by weight of 1 4 :5 :8-tetraamino-anthraquinone is divided into two portions. One portion is immersed for one minute at 15-20 C. in the above described aqueous dispersion of NN'-diphenylacetamidine. The fabric is then squeezed so that it retains approximately its own weight of liquid, and dried.

The portion of fabric which has been treated with NN'-diphenylacetamidine is exposed together with the untreated portion for 10 hours to the fumes of burning coal gas in an apparatus such as that previously described. At the conclusion of the test the untreated portion of the fabric is found to have considerably faded, the shade having become much duller, whereas the shade of the treated fabric has been afiected only to a slight degree.

Instead of employing an aqueous dispersion of NN'-diphenylacetamidine, the latter may be applied to the fabric in the 'form of a 1% (weight by volume) solution in ethyl alcohol, with similar results.

Example 2 A pattern of cellulose acetate artificial silk which has been dyed with 1% by weight of 1 :4 :5 :8-tetraaminoanthraquinone is immersed at about 20 C. in a 1% aqueous dispersion of N-methyl-NN'-diphenylacetamidine, which has been prepared irf the same manner as the amidine dispersion described in Example 1. After the fabric has been immersed for one minute it is removed from the dispersion,

squeezed until it holds about its own weight of liquid and then dried. When the so treated fabric is exposed to the fumes from burning coal gas, by the method described in the previous example, it suffers only a slight change in shade: on the other hand, when the untreated fabric is exposed to gas fumes under the same conditions, bad discolouration results.

In place of N-methyl-NN'-diphenylacetamidine, there may be employed with similar effect N-phenyl-N'-p-tolyl-N-methylacetamidine.

We claim:

1. The process for preventing or retarding the fading of dyesv on cellulose acetate when such colored materials are subjected to gas fumes, which comprises treating said cellulose acetate material with an N-N-diarylformamidine compound of the formula:

X x metal-l.

in which each R stands for an aryl radical of the group consisting of phenyl and tolyl radicals, and where each X stands for a substituent of the group consisting of H and alkyl groups containing not more than 4 carbon atoms.

2. Cellulose acetate material which is dyed with a color that is not fast to gas fumes on such material but which color on said material has been rendered fast to such fumes by having incorporated in the material an N.-N'-diaryl- 'formamidine compound of the formula:

x x RI I( J=,NR

in which each R stands for an aryl radical of the group consisting of phenyl and tolyl radicals, and where each X stands for a substituent of the group consisting of -H and alkyl groups containing not more than 4 carbon atoms.

3. Cellulose acetate material which is dyed with a color that is not fast to gas fumes on such materi l but which color on said material has been rendered fast to such fumes by having incorporated in the material N-N-diphenylformamidine.

4. Cellulose acetate material which is dyed with a color that is not fast to gas [fume on such material but which color on said material has been rendered fast. to such fumes by having incorporated in the material N-N-diphenylacetamidine.

CHARLES HUGH GILES. DONALD GRAHAM WILKINSON. 

